PhD in Optics and Quantum Matter (M/F)

Job Description

Thesis Subject

Context and Motivation
Achieving directional control of light–matter interaction is a major challenge for both fundamental physics and energy-related applications, particularly in the context of thermal radiation management and optical energy harvesting. A central limitation arises from optical reciprocity, which imposes symmetry between forward and backward propagation of electromagnetic waves in most systems.
Current photonic systems (such as solar cells) are limited by reciprocity symmetry, which prevents optimal directional control of light, thereby reducing their efficiency. Breaking reciprocity enables asymmetric reflection, absorption, and emission, and is therefore a key ingredient for advanced photonic functionalities. However, existing demonstrations typically rely on strong external magnetic fields, which significantly limit scalability and practical implementation.

Recently topological materials have emerged as promising platforms for achieving intrinsic non-reciprocity. In these materials, an external magnetic field is replaced by an intrinsic Berry curvature that manifests itself through an anomalous transverse response of electrons to an electric field. This transverse response can, in principle, induce non-reciprocal optical properties.

The purpose of this PhD project is to study whether intrinsic optical non-reciprocity can be:
• robustly demonstrated without an external bias,
• quantitatively predicted from realistic microscopic models,
• and extended to classes of materials beyond the initially targeted magnetic Weyl semimetals.

This PhD project addresses these challenges by combining microscopic modeling of materials, photonic design, and experimental validation of directional optical responses.

Objectives and work program:
The project aims to establish a comprehensive framework for intrinsic optical non-reciprocity through three main objectives:
• Microscopic modeling of optical conductivity: develop a realistic description of the frequency-dependent conductivity tensor σ(ω) using numerical approaches applicable to a wide class of materials.
• Experimental demonstration of intrinsic non-reciprocity: provide a clear and quantitative observation of directional reflectivity asymmetry (ΔR ≠ 0) in the absence of external magnetic fields, building on recent theoretical predictions
• Extension to complex photonic architectures: design and investigate photonic structures— ranging from thin films to structured and potentially patterned systems—maximizing directional optical contrast and relaxing symmetry constraints.

The project is expected to deliver:
• A thorough understanding of the mechanisms of optical non-reciprocity in topological
materials, validated by experimental measurements.
• The experimental demonstration of intrinsic non-reciprocity in Weyl thin films,
• The identification of new classes of materials exhibiting non-reciprocal optical properties, broadening the scope of potential applications.
• The publication of these results in high-impact journals and their dissemination through international conferences.

More broadly, this work will establish a new paradigm for controlling light using intrinsic material properties, with potential implications for thermal radiation engineering and energy systems

Your Work Environment

This PhD contract is funded by the CNRS's Mission for Cross-cutting and Interdisciplinary Initiatives (MITI). The project is an interdisciplinary collaboration between the Physics Laboratory at the ENS de Lyon and the Lyon Institute of Nanotechnologies.

The PhD candidate will benefit from two different and complementary environments: the Ecole Normale Supérieure (ENS) of Lyon and the Institute of Nanotechnologies in Lyon (INL) located in the Ecole Centrale and National Institute of Applied Sciences (INSA) of Lyon. These prestigious French grandes écoles are renowned for their excellence in research and higher education, training engineers, future academics and researchers in a highly selective and interdisciplinary environment.
The successful candidate will join a multidisciplinary team combining theoretical condensed matter physics, numerical modeling and experimental optics and photonics and with a solid experience of collaboration. This team is composed of a physicist specializing in solid-state physics (D. Carpentier), three specialists in photonics (H-S Nguen, Renwen Yu, M. Amara), one materials scientist (R. Bachelet), and an optical instrumentation engineer (Lotfi Berguiga). In addition, this project forms part of a
collective initiative aimed at structuring French research into topological materials and their applications in the energy sector. It will play an active role in several national networks which brings together national stakeholders to study the properties of topological materials, and in particular the optical and electromagnetic aspects.

Constraints and risks

-No identified risks.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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